Chasses are traditionally employed to encase and support electronic equipment, such as audio equipment, personal computers or television sets. Such electronic equipment requires electrical power to operate. A "line cord" is commonly employed to convey the necessary power from (typically) a wall outlet to the equipment.
In older equipment, line cords were permanently fixed (or "hard-wired") to their respective pieces of electronic equipment. One conventional configuration called for the line cord to exit the chassis through a modest aperture of perhaps twice the diameter of the cord. A compliant grommet or plastic through-hole clamp was interposed between the line cord and the edge of the aperture to protect the insulation about the line cord from being cut on the edge. A strain relief knot (in the case of a grommet) or the through-hole clamp itself further functioned to prevent any pulling forces that may be exerted on the line cord from being transmitted to its termination within the chassis, and thus reducing the risk of harm to the equipment.
Although hard-wired line cords were not dramatically disadvantageous (and, for that reason, are still in wide use today), some problems were experienced. For example, cord management became an issue with longer line cords. If the electronic equipment was desired to be moved, something had to be done about the line cord; either it was hastily wrapped around the chassis or bundled and tied to keep it neat. Further, as hard-wired line cords aged, they became brittle and tended to fatigue, particularly where they met the grommet or through-hole clamp. Because they were hard-wired, workmanlike replacement meant opening the chassis, disconnecting (perhaps by unsoldering) the line cord from its electrical connections in the chassis, untying any strain relief knot or releasing the through-hole clamp (not usually trivial) and finally reversing these steps to install the new line cord.
To address these disadvantages, more expensive electronic equipment is provided with removable line cords. One popular configuration calls for a countersunk plug to be located on a wall of the chassis. A line cord having a plug on one end and an outlet on the other is then employed. The outlet end is coupled to the countersunk plug and the plug end is plugged into a wall outlet. One widely-used type of plug and outlet is called an "IEC" (International Electrotechnical Commission) connector. IEC connectors are described, for example, in IEC Standard 60320, which is incorporated herein by reference. Those skilled in the pertinent art will recognize IEC connectors as being widely used in personal computers.
Unfortunately, removable line cords are not without their own problems. Perhaps the most common problem associated with using a removable line cord is the ease with which the line cord outlet can accidentally be separated from the plug on the chassis wall, having its most undesirable consequence when the equipment is being used. Separation may result if someone trips over a line cord or as the equipment itself is moved. Complete separation need not even occur; separation sufficient to break a single power connection to the chassis will interrupt the flow of current and cripple the equipment.
To address this problem, line cord retaining brackets were introduced. Today's line cord retaining brackets comprise a clamp that constricts about the body of the line cord outlet end. The clamp has two side-projecting flanges that, after the outlet is joined to the countersunk plug, are screwed to the chassis wall.
Although conventional line cord retaining brackets provide some benefits, they also bring some problems. First, conventional retaining brackets require multiple screws to affix the retaining brackets to the chassis wall. As a result, the task of coupling the retaining bracket to the chassis wall requires a screwdriver not only to clamp the bracket about the body of the line cord outlet, but also to mount the bracket to the chassis wall. Second, because the typical retaining bracket requires screws to hold it in position, the flanges must be large enough to accept the threads, and bear against the heads, of the mounting screws. As a result, conventional retaining brackets consume a significant amount of chassis wall area. As electronics chasses shrink, and their wall area is called upon to accommodate increasing numbers and sizes of features (such as switches, lights and cooling fans), the retaining bracket area penalty becomes evermore prominent.
Accordingly, what is needed in the art is a line cord retaining bracket that is faster and easier to couple to, and decouple from, a chassis wall, and occupies less area of the chassis wall, than those found in the prior art. In addition, what is needed in the art are methods of operating and manufacturing such retaining brackets.